Adhesive closure piece

ABSTRACT

The invention relates to an adhesive closure piece ( 10 ), comprising a substrate part ( 12 ) and closure pieces ( 20   a,    20   b ) of at least one type arranged upright thereon, said closure pieces each having a head part ( 14   a,    14   b ), which, at a free end face thereof has at least one contact surface ( 22   a,    22   b ) for detachably adhering to another component by means of adhesive force, wherein said adhesive closure piece is characterized in that at least one connection section ( 16   a,    16   b ) is present on the edge of at least one of the head parts ( 14   a,    14   b ), wherein said connection section protrudes beyond the edge of said head part ( 14   a,    14   b ) in at least one direction ( 30, 36 ) in such a way that the size of the contact surface ( 22   a,    22   b ) of the corresponding head part ( 14   a,    14   b ) is changed.

The invention relates to an adhesive closure piece, comprising a backing part and closure parts of at least a type that is arranged in an upright manner on said backing part and in each instance has a head part having a free end face, which has at least one contact surface for adhering to a second or third component by means of an adhesive force in such a way that the contact surface can be detached again.

WO 03/099951 A2 discloses methods for modifying the surfaces of an object in order to enhance the adhesive force of the object. For this purpose, the surface is subjected to a structuring process, so that a plurality of projections are formed; and each of these projections comprises a foot part and a head part, wherein the foot part has an end face that faces away from the surface. At the same time, each projection is dimensioned in such a way that all of the end faces have the same vertical height above the surface and form a common contact surface that is interrupted by a mutual spacing between the end faces. The projections are elastic and inclined in relation to the surface and are made of a material having a modulus of elasticity that is reduced in at least one of the reference directions, which comprise a longitudinal direction of each projection from the foot part to the head part and a transverse direction of each projection taken axially from the middle of the foot part to the outside. Portions of the contact surface can have a weaker separation force in order to facilitate an initial opening up of the adhesive connection, while other portions require a stronger separation force.

Contact surfaces in a magnitude of 0.2 to 0.5 μm² enable an interaction with a corresponding additional component (second or third component), to which the touch-and-close fastener part is to be secured by means of the so-called Van der Waals interaction, which is considered to be in classical terms a subgroup of adhesion. The prior art touch-and-close fastener part exhibits good connecting properties, but is associated with a time-consuming and, thus, cost-intensive manufacturing process. Since the arrangement between the head part, which typically has the shape of a mushroom, and the backing part by way of stem parts, which are arranged in such a way that they are exclusively inclined, is relatively rigid, there is still room for improved solutions with respect to the adhesion and separation properties of the touch-and-close fastener part or, more specifically, the individual closure parts.

Based on the above-described prior art, the object of the present invention is to enhance the adhesion and separation properties of the touch-and-close fastener part at a second or third component, so that it is possible to eliminate excessive loads on and damages to the closure parts.

This object is achieved with a touch-and-close fastener part having the features specified in claim 1 in its entirety. Since the edge of at least one of the head parts has, connected thereto, at least one connecting section, which projects beyond the edge of said head part in at least one direction in such a way that the result is a change in the effective size of the contact surface for the corresponding head part, the contact surface of at least one head part is modified in such a way that it is enlarged or decreased, and at least one tear-off edge is defined on the at least one connecting section; and this tear-off edge facilitates the separation of the contact surface from a second or third component.

It is expedient for the at least one connecting section to result in an enlargement of the corresponding contact surface; and it is especially preferred that the complete area of at least one connecting section be available as an additional contact surface.

A connection on the edge side means, as defined by the invention, that the at least one connecting section is connected to the respective head part in an edge region. This can be, for example, an edge section of the contact surface that is located on the end face side, but also a side section of the respective head part that is connected directly or indirectly to the contact surface. It is expedient for the at least one connecting section to be connected to the respective head part in an edge region on the end face side. Typically, the corresponding head part is designed in the shape of a mushroom and tapers off from the edge region on the end face side in the direction of the backing part or, more specifically, in the direction of a stem part that connects the respective head part with the backing part.

In a preferred embodiment of the touch-and-close fastener part according to the invention, the at least one connecting section extends in the direction of extension of the respective contact surface. In this arrangement, the at least one connecting section results in a widening of the respective contact surface in the direction of the respective extension; and it is especially preferred that the respective connecting section is connected directly to the respective contact surface in the direction of extension. However, it is also conceivable that the respective connecting section is arranged at a distance from the contact surface and/or is not connected to an edge region of the respective head part; wherein this edge region, which is located on the end face side, directly abuts the respective contact surface. In such designs, the entire contact surface exhibits a higher flexibility, because the contact surface on the end face side and the respective connecting section are connected to a third component in varying angular positions and can enter into an adhesive connection with this third component.

It is expedient that at least one connecting section has regions of varying width and/or thickness, in particular a thickness that decreases in the direction of the free edge, along the extension of the connecting section. As a result, the edge of the at least one connecting section or more specifically the respective contact surface has edge sections comparable to a thin lip that are easy to apply and detach. Furthermore, it is advantageous to make the at least one connecting section of the same material as the respective head part and, in particular, to mold said connecting section to this respective head part. In addition, the at least one connecting section and/or the corresponding head part can be an independent component that can be connected to the corresponding head part or more specifically the closure part. The result is the advantage that the respective connecting sections and/or head parts can be manufactured independently of the rest of the touch-and-close fastener part and can be connected to or placed on the closure part as a function of the respective application. In order to further develop specific properties of the connecting sections, it is possible to select a material other than the materials used for the rest of the closure parts. In particular, it is possible to select a material with good elasticity and adhesion properties.

At least one connecting section is designed preferably as a tooth, a serration, and/or a tab. The teeth, the serrations, and/or the tabs can be formed by molding at least one connecting section to the head part or by introducing notches or, respectively, recesses into the respective head part. In such an embodiment of the at least one connecting section, the tear-off edges that are arranged on the edge side are fixed in a defined way. It is expedient for the teeth, the serrations, and/or the tabs to have in each instance a shape in the form of a triangle. Furthermore, at least one connecting section can be designed in the manner of a comb and/or in the shape of a wave. A sinusoidal pattern of the free edge of the connecting section is also conceivable. Moreover, it is advantageous for a plurality, at least two, connecting sections to be provided on the respective head part. In this case, the connecting sections can preferably be arranged and/or formed at regular intervals on the respective head part, even more preferred along its edge. In so doing, identical or different connecting sections can be provided on a head part.

Additional features and advantages of the invention will become apparent from the figures and the following description of the drawings. The features illustrated in the figures are rendered in a highly schematic form and not drawn to scale. Referring to the drawings:

FIG. 1 is a top view of a touch-and-close fastener part according to the invention;

FIGS. 2 a-2 d are in each instance a top view of a modified head part according to the invention;

FIG. 3 is a sectional view of two closure part shown in FIG. 1; and

FIG. 4 shows a device for carrying out a method for manufacturing a touch-and-close fastener part according to the invention.

FIG. 1 shows a section of a touch-and-close fastener part 10 comprising a backing part 12, on which closure parts 20 a-20 i are arranged, of which a head part 14 a-14 i is visible in each instance. The head parts 14 a-14 i have in each instance connecting sections 16 a-16 i, which are arranged on the edge side, wherein the regular arrangement of the connecting sections produces an outer edge in the manner of a rosette on the head part. Furthermore, each head part 14 a-14 i and the corresponding closure part 20 a-20 i are designed in such a way that they are rotationally symmetrical relative to the respective center point 18 a-18 i. This feature offers the advantage that the properties of the respective head part 14 a-14 i or more specifically the closure part 20 a-20 i are identical in all radial directions. The maximum radial extension d_(a)-d_(i) of the respective head parts 14 a-14 i amounts to approximately 40 μm. In the illustrated exemplary embodiment, approximately twelve closure parts 20 a-20 i are arranged in a surface section of 200 μm×200 μm. As a result of the uniform design and the arrangement of the individual closure parts 20 a-20 i, the touch-and-close fastener part 10 exhibits homogeneous properties.

FIG. 2 a is an exploded view of the closure part 20 a and, respectively, the head part 14 a. The head part 14 a defines a contact surface 22 a on the illustrated end face. This contact surface has more or less the shape of a circle with a diameter D_(K), which is indicated with the circular line 26 a. An inner circular line 26 i indicates the radial extension D_(S) of the stem part 24. The contact surface 22 a is enlarged by the connecting sections 16 a, which are designed as teeth 28, arranged at regular intervals along the outer circular line 26 a.

An alternative embodiment of the connecting sections 16′, arranged on a head part 14′, is shown in FIG. 2 b. The connecting sections 16′ are designed as alternating teeth 28′ and tabs 32. The teeth 28′ are formed in each instance in the shape of a triangle and taper to a point in the radial direction 30. In contrast to the rectangular tabs 32, said teeth have a larger extension in the radial direction 30, but have a smaller extension along the outer circular line 26 a. Even in the embodiment shown in FIG. 2 b, the connecting sections 16′, which are connected directly to the contact surface 22′ in the radial direction 30 and have the shape of teeth 18′ and tabs 32, result in an enlargement of the contact surface.

FIG. 2 c shows the outer contour of a contact surface 22″, where this outer contour exhibits the pattern of an n-on, here a hexagon. Six identical connecting sections 16″ in the form of triangular teeth 28″ are molded to a head part 14″ that has the shape of a mushroom, thus forming the so-called hexagonal outer contour of the contact surface 22″.

FIG. 2 d shows a contact surface 22′″ having a size that is enlarged by tabs 32′″ and comb sections 34 that are connected to the edge of the triangular contact surface 22′″ or more specifically the head part 14″. The three comb sections 34 are arranged along the sides of the equilateral triangle; and the tabs 32′″ are arranged at the three corners of the equilateral triangle. FIG. 2 d shows very clearly that the shape of the head part 14′″ is not limited to a mushroom, i.e., a round shape, but rather can also have an angular shape.

FIG. 3 is a longitudinal view of the closure parts 20 a, 20 b of the touch-and-close fastener part 10 shown in FIG. 1. The closure parts 20 a, 20 b stand more or less perpendicular on the backing part 12; and the contact surfaces 22 a, 22 b, which are formed on the head parts 14 a, 14 b, extend in each instance more or less parallel to the backing part 12 and, in addition, in a plane spaced equidistant x₃ from the backing part 12. The major distinction between the two closure parts 20 a, 20 b lies in the fact that the stem part 24 a extending from the head part 14 a to the backing part 12 has in essence the same thickness D_(S), whereas the stem part 24 b has a tapering y₂ and a widening y₃. The connecting sections 16 a that are connected to the head part 14 a on the edge side extend in conformity with the contact surface 22 a in the radial direction 30 and enlarge, when directly connected, the contact surface 22 a.

In contrast, the connecting sections 16 b, provided on the head part 14 b, are oriented transversely to the radial direction 30 and to the axial direction 36. The end face of the contact surface 22 b, which is enlarged by the connecting sections 16 b, has surface regions, which are oriented in a radial direction 30, and surface regions, which are oriented transversely to the radial direction 30. It is very clear from FIG. 3 that the respective connecting sections 16 a-16 b are designed in the form of a thin lip and have a thickness that decreases in the direction of the free edge. However, alternative solutions are also conceivable. For example, the respective connecting section can be connected to the free outer edge of the corresponding head part in such a way that said connecting section has a constant thickness or, respectively material strength without tapering outwards in the form of a lip, a feature that results, in this respect, in an advantageous support of the above-described tear-off edge or the tear-off line. The illustrated rotational symmetry of the closure parts 20 a and 20 b is practical in terms of rotational invariance properties.

FIG. 4 illustrates the method for manufacturing the touch-and-close fastener part 10. A synthetic plastic material, which is extruded from an extruder head 40, is conveyed between a pressure roller 42 and a forming roller 44. The pressure roller 42 moves into a first movement direction 46; the forming roller 44 moves into a second movement direction 48 that is opposite the first movement direction 46. The shell of the forming roller 44 is provided with a forming screen 50, in which mold cavities 52 are formed in conformity with the closure parts 20 that are to be formed. The mold cavities 52 are formed on an interior 54 in conformity with the head parts 14 a-14 c and the connecting sections provided on said head parts. The rotational movement of both rollers 42, 44 forces the synthetic plastic material, which is fed into a gap that is formed by said two rollers, into the mold cavities 52 of the forming screen 50; and the closure parts 20 are made of a synthetic plastic material on the side of the backing part 12 that is assigned to the forming roller 44. After the closure parts 20 have cured and are demolded or, more specifically, removed from the corresponding mold cavities 52, a touch-and-close fastener part 10, comprising a backing part 12 and closure parts 20, 20′, which are arranged to stand upright on said backing part, with head parts 14, 14′ is ready for immediate use. Then the forming screen 50 has, when viewed from the free end face, mold recesses, as shown, by way of example, in FIG. 1 for a completed head shape of the end product. Instead of an extrusion process using preferably thermoplastic materials, it is also possible to process two component mixtures or multicomponent mixtures, such as polyvinyl siloxane, using mold cavities.

The backing part 12 is made in an advantageous way in one piece with the closure parts 20, 20′. Furthermore, the respective synthetic plastic material can be processed by means of microreplication technology. Other methods for manufacturing the touch-and-close fastener part or more specifically the closure parts 20 include not only the chill method and the roll method, but also microlithographic or nanolithographic methods, including so-called micro printing. In any event, the described microstructure can also be achieved with a kind of crystal growth. Moreover, the closure material can also be generated from solids, for example, with the use of micro spark erosion or a suitable laser beam machining.

In addition, the invention provides that the closure parts 20, 20 a-20 i can be fabricated separately, stockpiled, and/or transported and connected, as required, to a corresponding backing part 12 or rather can be arranged on said backing part. In particular, different kinds of closure parts, for example, adhesive closure parts modified according to the invention, interlocking parts, and loop parts, can be arranged on a backing part 12. Other functional elements can be provided, as a function of the application, on the backing part 12; and, in particular, the closure parts can be arranged on one side or both sides of the backing part 12. 

1. An adhesive closure piece (10), comprising a backing part (12) and closure parts (20, 20 a-20 i) of at least a type that is arranged in an upright manner on said backing part and in each instance has a head part (14 a-14 i, 14′-14′″) having a free end face, which has at least one contact surface (22 a-22 i, 22′-22′″) for adhering to a second or third component by means of an adhesive force in such a way that the contact surface can be detached again, characterized in that the edge of at least one of the head parts (14 a-14 i, 14′-14′″) has, connected thereto, at least one connecting section (16 a-16 i, 16′-16′″), which projects beyond the edge of said head part (14 a-14 i, 14′-14′″) in at least one direction (30, 36) in such a way that the result is a change in the size of the contact surface (22 a-22 i, 22′-22′″) for the corresponding head part (14 a-14 i, 14′-14′″).
 2. The touch-and-close fastener part according to claim 1, characterized in that the at least one connecting section (16 a-16 i, 16′-16′″) results in an enlargement of the corresponding contact surface (22 a-22 i, 22′-22′″).
 3. The touch-and-close fastener part according to claim 1, characterized in that the at least one connecting section (16 a-16 i, 16′-16′″) is provided, in particular molded, on an end face-side edge region of the respective head part (14 a-14 i, 14′-14′″).
 4. The touch-and-close fastener part according to claim 1, characterized in that at least one connecting section (16 a-16 i, 16′-16′″) extends or more specifically faces in the direction (30) along the extension of the respective contact surface (22 a-22 i, 22′-22′″).
 5. The touch-and-close fastener part according to claim 1, characterized in that at least one connecting section (16 a-16 i, 16′-16′″) is inclined relative to the extension of the respective contact surface (22 a-22 i, 22′-22′″) and preferably faces away from the backing part (12).
 6. The touch-and-close fastener part according to claim 1, characterized in that at least one connecting section (16 a-16 i, 16′-16′″) has regions of varying width and/or thickness, in particular a thickness that decreases in the direction of the free edge, along the extension of the connecting section.
 7. The touch-and-close fastener part according to claim 1, characterized in that the at least one connecting section (16 a-16 i, 16′-16′″) is made of the same material as the respective head part (14 a-14 i, 14′-14′″) and, in particular, is molded to said head part.
 8. The touch-and-close fastener part according to claim 1, characterized in that the at least one connecting section (16 a-16 i, 16′-16′″) and/or the respective head part (14 a-14 i, 14′-14′″) is designed as an independent component that can be connected to the corresponding head part (14 a-14 i, 14′-14′″) or more specifically to the closure part (20, 20 a-20 i).
 9. The touch-and-close fastener part according to claim 1, characterized in that at least one connecting section (16 a-16 i, 16′-16′″) is designed as a tooth (18-18′″), a serration, and/or a tab (32, 32′″).
 10. The touch-and-close fastener part according to claim 1, characterized in that at least one connecting section (34) is designed in the manner of a comb and/or in the shape of a wave.
 11. The touch-and-close fastener part according to claim 1, characterized in that a plurality, at least two, connecting sections (16 a-16 i, 16′-16′″) are arranged and/or formed preferably at regular intervals on the respective head part (14 a-14 i, 14′-14′″). 